tiny-future

Future

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Future uses less than 10 lines of code to change the usage of Promise.

Allow Promise to call resolve/reject anywhere, just like C# TaskCompletionSource, without being restricted to the executor that creates Promise.

[!NOTE] Future uses Promise.withResolvers to create Promise, if Promise.withResolvers is not available, Future will fall back to a regular Promise.

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Installation

# via pnpm
pnpm add tiny-future
# or via yarn
yarn add tiny-future
# or just from npm
npm install --save tiny-future
# via JSR
jsr add @happy-js/tiny-future
# for deno
deno add @happy-js/tiny-future
# for bun
bunx jsr add @happy-js/tiny-future

Example

import { Future } from 'tiny-future';

function sleep(ms: number):Promise<number> {
    const future = new Future<number>();

    setTimeout(() => {
        // future.resolve/future.reject at anywhere
        future.resolve(0);
    }, ms);

    return future.promise;
}

await sleep(1000);

If you have used C# TaskCompletionSource, then you should be familiar with the usage of Future.

Compare to the usual way of creating Promise.

function sleep(ms: number): Promise<number> {
    return new Promise((resolve) => {
        setTimeout(() => {
            // resolve/reject must in the executor closure
            resolve(ms);
        }, ms);
    });
}

await sleep(1000);

Docs